BEAUMAN, R. L.; KAHN, P. F.; MENDON�A, M. T.; Auburn University: Short-term effects of burrow collapse on corticosterone levels and immune response of gopher tortoises

The gopher tortoise is a federally listed species in the western portion of its range, and a species of concern elsewhere. Their burrows are often collapsed and tortoises become entombed during human activity associated with land use and development. To determine how detrimental this disturbance is to tortoises, we experimentally collapsed burrows over two seasons (Fall, 2003 and Spring, 2004) using military and forestry equipment. Tortoises (N=42) were trapped prior to the collapse and blood samples taken to establish baseline levels of corticosterone. Additionally, the animals underwent a series of stress and immune (T cell and B cell) challenges. Then a transmitter was attached, they were returned to their home burrow, and movements tracked for 30 days. We then collapsed their burrows near the mouth with either an M113 armored personnel carrier (N=10) or a JD 648 skidder (N=32). We monitored the number of days until each tortoise excavated itself. Animals were re-bled shortly after self-excavation for basal corticosterone and re-administered the stress and immune challenges. Subsequent movement was also tracked. All but two tortoises self-excavated within 51 days: the majority within 20 days. In the Fall 2003 experiment, corticosterone level was significantly, positively correlated with the number of days tortoises were entombed. Males and females exhibited inverse patterns of T cell response to entombment period. Additional differences in stress and immune responses will be discussed.